1. Field of the Invention
The present invention relates to an air bag system for vehicles, and more particularly to an improved passenger air bag system for vehicles wherein the structure of the passenger air bag system is simple, the size of the passenger air bag system is reduced, and the assembly operation of the passenger air bag system is easy and convenient.
2. Description of the Related Art
Generally, an air bag system for vehicles is mounted in front of a driver seat or a passenger seat in such a manner that a cushion of the air bag system is instantly expanded when a collision of the vehicle occurs for protecting a driver or a passenger from injury.
The air bag systems may be classified into a driver air bag system and a passenger air bag system. The driver air bag system is mounted to the steering wheel of the vehicle for protecting the driver from injury. The passenger air bag system is mounted to an instrument panel of the vehicle disposed in front of the passenger seat for protecting the passenger from injury. Basically, the driver air bag system is requisite, and the passenger air bag system is optional; however, vehicles with passenger air bag systems basically mounted therein for protecting passengers from injury are on the increase in recent years.
FIG. 1 is a perspective view showing a conventional passenger air bag system, and FIG. 2 is a cross-sectional view showing the conventional passenger air bag system.
As shown in FIGS. 1 and 2, the conventional passenger air bag system for vehicles comprises: an air bag housing 6 mounted to an instrument panel 2 and to a cowl cross member 4; an inflator 8 attached to the air bag housing 6 for discharging gas when a collision of the vehicle occurs; a connector 10 having one end connected to the inflator 8 for transmitting electric current and an operation signal from an external device to the inflator 8; a cushion 12 accommodated in the air bag housing 4 such that the cushion 8 is expanded to the front of a passenger seat by means of the gas discharged from the inflator 8; and a retainer 14 attached to the air bag housing 6 for supporting the cushion 12.
The air bag housing 6 comprises: a cushion housing 16 formed in the shape of a box with the front part opened so that the cushion 12 is accommodated in the cushion housing 16 while being folded; and a can housing 18 connected to the rear part of the cushion housing 16, in which the inflator 8 is disposed.
The cushion housing 16 is provided along both longitudinal sides at the front part thereof with flanges 16a, respectively, which are fixed to the rear part of the instrument panel 2 by means of bolts. At the instrument panel 2, to which the cushion housing 16 is attached, is formed a crush pad 2a having a cut line, by which the crush pad 2a is easily broken when the cushion 12 is expanded.
The crush pad 2a of the instrument panel 2 constructed as described above is smoothly broken by means of the cushion 12 expanded by the gas discharged from the inflator 8 when a collision of the vehicle occurs, whereby the cushion 12 is rapidly expanded toward a passenger seated in the passenger seat.
The can housing 18 is connected to the rear part of the cushion housing 16 in such a manner that the can housing 18 communicates with the cushion housing 16. The can housing 18 is attached to the cowl cross member 4 in the instrument panel 2 by means of a mounting bracket 20.
One end of the mounting bracket 20 is fixed to the side part of the can housing 18 by means of a bolt, and the other end of the mounting bracket 20 is fixed to a prescribed area of the outer circumference of the cowl cross member 4 by means of a bolt.
Consequently, the air bag housing 6 is disposed between the instrument panel 2 and the cowl cross member 4 in such a manner that the front part of the air bag housing 6 is fixed to the instrument panel 2, and the rear part of the air bag housing 6 is fixed to the cowl cross member 4.
The inflator 8 is formed in the shape of a cylinder. The inflator 8 is longitudinally disposed in the can housing 18, and both ends of the inflator 8 are fixed to the can housing 18. The inflator 8 is connected to an external device, such as an electronic control unit (not shown) and a power supply terminal (not shown) via the connector 10.
When a collision of the vehicle occurs, an operation signal is transmitted from the electronic control unit to the inflator 8. The inflator 8 is exploded by means of electric current supplied from the power supply terminal for generating gas having more than a prescribed pressure.
The cushion 12 is mounted in the can housing 18 together with the retainer 14 in such a manner that the inlet part of the cushion 12 communicates with a gas-guiding hole 14a formed at the center of the retainer 14.
In the conventional passenger air bag system for vehicles with the above-stated construction, the operation signal is transmitted from the electronic control unit to the inflator 8 via the connector 10 when a collision of the vehicle occurs, and then the inflator 8, to which electric current is supplied from the power supply terminal, is exploded to generate gas.
The gas generated by means of inflator 8 flows along the can housing 18 so that the gas is guided through the gas-guiding hole 14a of the retainer 14. The gas flowing through the gas-guiding hole 14a of the retainer 14 is introduced into the cushion 12 through the inlet part of the cushion 12.
The cushion 12 is expanded at prescribed pressure and speed by means of the gas introduced into the cushion 12. The crush pad 2a of the instrument panel 2 is broken by means of the cushion 12 expanded as described above. Subsequently, the cushion 12 is further expanded toward the passenger seated in the passenger seat.
Consequently, shock transmitted to the passenger when a collision of the vehicle occurs is effectively absorbed by means of the cushion 12 expanded as described above, and thus injury to the passenger is minimized.
In the conventional passenger air bag system for vehicles, however, the can housing 18 having the inflator 8 disposed therein is fixedly attached to the cowl cross member 4 by means of the mounting bracket 20. That is to say, the mounting bracket 20 is unavoidably used in the conventional passenger air bag system for vehicles. Consequently, the number of components of the passenger air bag system is increased, and the assembly operation of the passenger air bag system is very complicated.
Especially, the space between the instrument panel 2 and the cowl cross member 4 is very small and narrow. As a result, the size and the shape of the air bag housing 6 are excessively restricted. Furthermore, the conventional air bag system may interfere with other components of the vehicle when the air bag system is assembled or operated.